Toilet for Cabin

I have a challenge. I'm part of a group that has a turn-of-the twentieth century cabin with a failing toilet. The current system employs an overhead tank with vacuum check valve that drains when the well pump is turned off. The tank is filled when a person sits on the seat, the water is released when they get up. The bowl drains directly into the pit. This toilet is vintage 1940 and parts are no longer available. What makes this toilet valuable to us is that no one has to winterize it. Simply turn off the pump and walk away. However, the fill valve on the seat has failed and without parts, we need to replace the toilet.

There is no heat in this cabin other than a couple of wood stoves. The bathroom (when the cabin is occupied) stays above freezing, but when left for months in the winter is subject to temps as low as 10.

We need a solution that does not involve heaters, anti-freeze or other human intervention because we can't count on a guest (borrowing the cabin) to have the skills to execute simple winterizing directions. Sad but true, too many people just don't have the skills to survive without batteries.